Athey Kangal

Vasantha discovers her husband Ranganathan is murdered; a masked killer also tries to kill her, but she escapes. The attack plunges the household into fear and sets the police investigation in motion. The crime establishes the haunting threat that will shadow the rest of the story.

Vasantha is left in a state of shock and becomes mentally paralysed. A formal case is registered, and investigators begin piecing together clues. The house becomes a crime scene under the looming presence of a killer.

Susi, a college student, arrives with friends to stay at Vasantha's house. The household includes Kamalanathan, Vimalanathan, aunt Vasantha, the butler Appukutty Nair, and the visiting doctor Vedamurthy. Their presence adds new voices to the investigation and a sense of domestic normalcy that will soon be shattered.

A series of murders unfold within the house, each marked by an intentionally left cigar bit. The killer toys with the residents, escalating fear and paranoia. Clues pile up as investigators chase a signature pattern.

Despite tight security, the killer targets Vasantha and she is killed. The brutal act compounds the mystery and makes Susi a more prominent target. The investigation intensifies as the killer's pattern becomes more personal.

Baskar, Susi's colleague, takes up the case and begins interrogating Vimalanathan, Kamalanathan, and the other inmates. He hunts for alibis and connections, tracing the cigar clues through the household. The tension between suspects grows as fear spreads.

Baskar follows Kamalanathan to a strange house and encounters Mala, Kamalanathan's lover who had been rescued years earlier after a suicide attempt. The discovery deepens Kamalanathan's secretive image and hints at motives tied to love and loyalty. Kamalanathan reveals his plan to marry Mala only after Susi is married.

Baskar orders everyone to stay out for a night to lure the killer. The intruder slips into Susi's room with intent to kill, but Baskar cannot reveal the killer’s identity and only sees his eyes before the mask is dropped and the killer escapes. The narrow capture raises the stakes for the investigation.

Baskar discovers Vimalanathan murdered on the house doorstep, confirming the killer's brutal reach. The murder chills the household and adds urgency to uncovering the truth. The killer now seems to be among the suspects with inside knowledge.

Kamalanathan urges everyone to vacate the house around Susi's birthday party. The murderer makes another attempt on Susi, but Baskar saves her. He chases the killer but loses track, deepening the mystery.

On his return from the chase, Baskar discovers Vedamurthy injured and rescues him. Vedamurthy becomes a person of interest in the investigation and the doctor’s loyalties come into focus. The night’s events heighten the sense that the killer is closer than anyone suspects.

Kamalanathan reveals that his father had an extramarital affair and that a fire killed the lover and her 10-year-old son. Baskar theorizes that the son may still be alive and could be the killer seeking vengeance. The family history becomes a central motive driving the murders.

Baskar uses the killer's eye pattern as a test by showing the mask to each man present. The eyes match reveal Vedamurthy as the killer, who had been disguising himself with prosthetics. The revelation exposes the doctor’s deception and clears others.

The killer tries to escape and is injured in a chase. He slips away through a tunnel near the garden, leading to a secret room beneath the garden that connects to his hidden house and corpse. The revelation explains how the murders were carried out and why they kept occurring.

With the mystery resolved, Baskar marries Susi and stays in the same house, while Kamalanathan marries Mala. The couple’s union signals a return to normalcy and a fresh start after the terror that haunted them. The house becomes their shared home and a symbol of new beginnings.